Headphone Amps

A/B Comparison #1

• Sigma 22 power supply.
• Three-channel "Active Ground" topology.
• See http://www.amb.org/audio/beta22/

LCD-2

I was very hard pressed to hear ANY difference between the Beta 22 and the M³ on the LCD-2's. MAYBE a touch better bass control on the Beta 22 but then again maybe not.  I would NOT bet money on me being able to tell these two amps apart in a blind test with the LCD-2.

HD-800

With the somewhat exaggerated highs of the HD800's  I began to hear a subtle difference between the two amps.  The highs on the M³ sounded a tad bit harsh.  Also, the "separateness" of various instruments on a track was better with the Beta22. But these differences were quite subtle.

MY CONCLUSIONS

1. I was surprised that I didn't immediately hear incontrovertible differences between these amps. I was expecting a fairly obvious difference in their sounds.

2. These are both good amps- they both sounded pretty wonderful.

The Beta 22 and M³ amps have things in common-  MOSFET output stages, 3-channel "active ground" design- maybe this is why any differences I may have heard were so subtle.

This makes me want to A / B others amps.  I also urge anyone reading this post who owns more than one headphone amp to build their own A / B box and report on your tests.

I expect I will hear more noticeable differences with other amps - such as Cavilli-Kumisa  vs. Beta 22, and also Beta 22 vs various tube amps in my collection.

Below: my Beta 22. In three-channel form, this amp seems quite sensitive to magnetic field noise- I had hum until I put the power transformer in a steel box, you can see it in a grey steel Hammond enclosure there at the lower left. If I had to do it again, I would build this amp as a 2-chassis design.